Gamegirl: the retro console done right

[davidperrenoud]

Hello,

I wanted to ask your advice about my recent project:

https://hackaday.io/project/10207-gamegirl-the-retro-console-done-right

Some technical details especially for you electricians:

• HDMI/DPI mode for the display (no SPI protocol rubbish!)
• MCP73831 battery charger
• PAM8302 amplifier + low-pass RC filter + audio through PWM1 on the Pi
• Backlight through PWM0 or PCM_CLK
• No boost converter

For this last point, has anyone tried to power a Raspberry Pi directly from a Li-Po (3.7V-4.2V) connected to both the 5V and 3.3V connector?

I think the BCM2835 can tolerate the higher voltage on the 3.3V rail. The 5V rail has to be connected because the switching mode power supply (PAM2306) uses it to power the 1.8V rail.

[Mechanical Menace]

Personally I'd say it's not a retro style console, just another RPi with some emulators in a gameboy style case. How would it be better than a phone in one of the many gaming cases that are cheaply available?

Not saying it's not a cool little project but calling it "a retro console done right" is misleading at best. Can you even do bare metal coding on a Pi and use all the peripherals? As somebody who likes messing with coding for retro consoles from the 8 bit era up to the Wii (no OS getting in the way so in my view the last retro console from a devs point of view) the inability to try and get more out of the machine because of that limitation would put me off of bothering with it given the tag line.

EDIT:Also what "retro homebrew dev" wants to be writing games and/or apps as Lua scripts? A quick search told me your first 3 poll options could just be replaced with one option, "using Lua."

EDIT the 2nd: Really don't mean to sound so down on the project. It really is cool. Throw in devkits for the emulated machines, HDMI out, and some way to connect a keyboard and it could be "The ultimate retro emulation station and devkit." Make enough I/Os available to allow people to use it as a 8 or 16 bit cartridge with adapters on some sort of expansion port and even better.

[davidperrenoud]

It's better than a phone because it's made to only play games. For developers, you can customise the hardware in any way you want and the software stack is much thinner (OpenELEC + RetroArch + C or Lua).

If you want a bare metal console, it's maybe easier to start with an Arduboy. Of course it won't be as powerful and you won't have all the ease of use of a filesystem, OpenGL, USB peripherals, etc.

But you can actually do bare metal on a Pi and that would be really cool if someone tried it. You would have to find a way to enable the DPI mode, do PWM audio and read the buttons:
http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/index.html